Question 1

When the intercept in a regression equation is deemed not significantly different from 0,then in making predictions for y,0.0 should be used as the value of the intercept rather than the estimated intercept value.

Accepted Answer

A) True 
 B)False

Question 2

Which of the following is NOT an assumption for the simple linear regression model?

Accepted Answer

A) The individual error terms are statistically independent. 
B) The distribution of the error terms will be skewed left or right depending on the shape of the dependent variable. 
C) The error terms have equal variances for all values of the independent variable. 
D) The mean of the dependent variable value for all levels of x can be connected by a straight line.

Question 3

When regression analysis is used for descriptive purposes,two of the main items of interest are whether the sign on the regression slope coefficient is positive or negative and whether the regression slope coefficient is significantly different from zero.

Accepted Answer

A) True 
 B)False

Question 4

When a correlation is found between a pair of variables,this always means that there is a direct cause and effect relationship between the variables.

Accepted Answer

A) True 
 B)False

Question 5

The following regression output was generated based on a sample of utility customers.The dependent variable was the dollar amount of the monthly bill and the independent variable was the size of the house in square feet.  Based on this regression output,what is the 95 percent confidence interval estimate for the population regression slope coefficient?

Accepted Answer

A) Approximately -0.0003 ----- +0.0103 
B) About -0.0082 ----- +0.0188 
C) Approximately -32.76 ----- +32.79 
D) None of the above

Question 6

Consider the following partially completed computer printout for a regression analysis where the dependent variable is the price of a personal computer and the independent variable is the size of the hard drive.  Based on the information provided,which of the following statements is true if alpha = .05?

Accepted Answer

A) The slope is not significantly different from 0 because p-value = 0.84 is greater than 0.05 
B) The slope is significantly different from 0 because p-value = 9.95 is greater than 0.05 
C) The slope is not significantly different from 0 because p-value = 9.95 is greater than 0.05 
D) The slope is significantly different from 0 because p-value = 9.95En - 10 is less than 0.05

Question 7

A study was recently performed by the Internal Revenue Service to determine how much tip income waiters and waitresses should make based on the size of the bill at each table.A random sample of bills and resulting tips were collected.These data are shown as follows:  Based upon these data,what is the approximate predicted value for tips if the total bill is $100?

Accepted Answer

A) $15.55 
B) $20.61 
C) $26.03 
D) $12.88

Question 8

Which of the following is a correct interpretation for the regression slope coefficient?

Accepted Answer

A) For a one-unit change in y,we can expect the value of the independent variable to change by b1 units on average. 
B) For each unit change in x,the dependent variable will change by b1 units. 
C) The average change in y of a one-unit change in x will be b1 units. 
D) The average change in x of a one-unit change in y will be b1 units.

Question 9

Given the data below,one ran the simple regression analysis of Y on X.  The relationship between Y and X is

Accepted Answer

A) significant at the alpha = 1 percent level. 
B) significant at the alpha = 5 percent level. 
C) significant at the alpha = 10 percent level. 
D) not significant at the alpha = 10 percent level.

Question 10

In a study of 30 customers' utility bills in which the monthly bill was the dependent variable and the number of square feet in the house is the independent variable,the resulting regression model is  = 23.40 + 0.04x.Given this model,for a customer with a 2,000 square foot house and a monthly utility bill equal to $100.00,the residual from the regression model is approximately -$3.40.

Accepted Answer

A) True 
 B)False

Question 11

A high coefficient of determination (R2)implies that the regression model will be a good predictor for future values of the dependent variable given the value of the independent variable.

Accepted Answer

A) True 
 B)False

Question 12

Recently,an automobile insurance company performed a study of a random sample of 15 of its customers to determine if there is a positive relationship between the number of miles driven and the age of the driver.The sample correlation coefficient is r = .38.Given this information,which of the following is appropriate critical value for testing the null hypothesis at an alpha = .05 level?

Accepted Answer

A) t = 2.6104 
B) t = 1.7613 
C) t = 1.7531 
D) t = 1.7709

Question 13

If two variables are related in a positive linear manner,the scatter plot will show points on the x,y space that are generally moving from the lower left to the upper right.

Accepted Answer

A) True 
 B)False

Question 14

A correlation coefficient computed from a sample of data values selected from a population is called a statistic and is subject to sampling error.

Accepted Answer

A) True 
 B)False

Question 15

If a residual plot exhibits a curved pattern in the residuals,this means that:

Accepted Answer

A) the errors are not normally distributed. 
B) there must be a curvilinear relation between x and y. 
C) there is no significant relation between x and y. 
D) there is a problem with constant variance.

Question 16

The sign on the intercept coefficient in a simple regression model will always be the same as the sign on the correlation coefficient.

Accepted Answer

A) True 
 B)False

Question 17

When the correlation coefficient for the two variables was -0.23,it implies that the two variables are not correlated because the correlation coefficient cannot be negative.

Accepted Answer

A) True 
 B)False

Question 18

Explain why it is important to construct scatter plots prior to conducting regression analysis.

Accepted Answer

The answer of Explain why it is important to construct...

Question 19

Which of the following statements is true with respect to a simple linear regression model?

Accepted Answer

A) The percent of variation in the dependent variable that is explained by the regression model is equal to the square of the correlation coefficient between the x and y variables. 
B) If the correlation coefficient between the x and y variables is negative,the sign on the regression slope coefficient will also be negative. 
C) If the correlation between the dependent and the independent variable is determined to be significant,the regression model for y given x will also be significant. 
D) All of the above are true.

Question 20

What factors are of importance to an analyst when linear regression analysis is used for descriptive purposes?

Accepted Answer

The answer of What factors are of importance to an...

Exam 14: Introduction to Linear Regression and Correlation Analysis

When the intercept in a regression equation is deemed not significantly different from 0,then in making predictions for y,0.0 should be used as the value of the intercept rather than the estimated intercept value.

Which of the following is NOT an assumption for the simple linear regression model?

When regression analysis is used for descriptive purposes,two of the main items of interest are whether the sign on the regression slope coefficient is positive or negative and whether the regression slope coefficient is significantly different from zero.

When a correlation is found between a pair of variables,this always means that there is a direct cause and effect relationship between the variables.

Which of the following is a correct interpretation for the regression slope coefficient?

Given the data below,one ran the simple regression analysis of Y on X. The relationship between Y and X is

A high coefficient of determination (R²)implies that the regression model will be a good predictor for future values of the dependent variable given the value of the independent variable.

If two variables are related in a positive linear manner,the scatter plot will show points on the x,y space that are generally moving from the lower left to the upper right.

A correlation coefficient computed from a sample of data values selected from a population is called a statistic and is subject to sampling error.

If a residual plot exhibits a curved pattern in the residuals,this means that:

The sign on the intercept coefficient in a simple regression model will always be the same as the sign on the correlation coefficient.

When the correlation coefficient for the two variables was -0.23,it implies that the two variables are not correlated because the correlation coefficient cannot be negative.

Explain why it is important to construct scatter plots prior to conducting regression analysis.

Which of the following statements is true with respect to a simple linear regression model?

What factors are of importance to an analyst when linear regression analysis is used for descriptive purposes?